866856431 has 4 divisors (see below), whose sum is σ = 990693072. Its totient is φ = 743019792.

The previous prime is 866856413. The next prime is 866856491. The reversal of 866856431 is 134658668.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-866856431 is a prime.

It is a super-2 number, since 2×866856431² = 1502880143932115522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (866856491) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61918310 + ... + 61918323.

It is an arithmetic number, because the mean of its divisors is an integer number (247673268).

Almost surely, 2^866856431 is an apocalyptic number.

866856431 is a deficient number, since it is larger than the sum of its proper divisors (123836641).

866856431 is a wasteful number, since it uses less digits than its factorization.

866856431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123836640.

The product of its digits is 829440, while the sum is 47.

The square root of 866856431 is about 29442.4256983014. The cubic root of 866856431 is about 953.4890834609.

The spelling of 866856431 in words is "eight hundred sixty-six million, eight hundred fifty-six thousand, four hundred thirty-one".